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NetDrop[chain,n]

removes the first n layers from a NetChain.

NetDrop[chain,-n]

removes the last n layers from a NetChain.

NetDrop[chain,{start,end}]

drops the layers between start and end in a NetChain.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Possible Issues  
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NetDrop

NetDrop[chain,n]

removes the first n layers from a NetChain.

NetDrop[chain,-n]

removes the last n layers from a NetChain.

NetDrop[chain,{start,end}]

drops the layers between start and end in a NetChain.

Details

  • For NetDrop[chain,{start,end}], the start and end can be given as an integer n, which specifies the n^(th) layer, or "name", which specifies a named layer in a NetChain that was constructed using <|"name"->layer,…|>.
  • When removing layers from the interior of a NetChain, the input shape of the first removed layer and the output shape of the last removed layer must match.
  • Any NetEncoder or NetDecoder that is present on the chain will be preserved, if possible.
  • NetDrop[net,spec,"port1"->spec1,…] can be used to give types for the input and/or output of the resulting NetChain or NetGraph, using the normal type specifications those functions allow. The new port specifications will replace any existing NetEncoder, NetDecoder or type.

Examples

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Basic Examples  (2)

Construct a chain consisting of four layers:

Wolfram Language code: chain = NetChain[{Ramp, Sin, Cos, Tanh}]

Drop layers from the beginning of the chain:

Wolfram Language code: NetDrop[chain, 2]

Drop layers from the end of the chain:

Wolfram Language code: NetDrop[chain, -2]

Drop layers from the middle of a chain:

Wolfram Language code: NetDrop[chain, {2, 3}]

Drop layers from the middle of a chain, referring to them by name:

Wolfram Language code: chain = NetChain[<|"a" -> Ramp, "b" -> Sin, "c" -> Cos, "d" -> Tanh|>]
Wolfram Language code: NetDrop[chain, {"b", "c"}]

Scope  (1)

Add a new NetDecoder while dropping layers:

Wolfram Language code: net = NetChain[{3, LogisticSigmoid, SummationLayer[]}]
Wolfram Language code: NetDrop[net, -1, "Output" -> NetDecoder["Class"]]

Possible Issues  (1)

When removing layers from the interior of a NetChain, the input shape of the first removed layer and the output shape of the last removed layer must match:

Wolfram Language code: chain = NetChain[<|"a" -> 1, "b" -> 2, "c" -> 3, "d" -> 4|>]
Wolfram Language code: NetDrop[chain, {"b", "c"}]
Wolfram Research (2018), NetDrop, Wolfram Language function, https://reference.wolfram.com/language/ref/NetDrop.html.

Text

Wolfram Research (2018), NetDrop, Wolfram Language function, https://reference.wolfram.com/language/ref/NetDrop.html.

CMS

Wolfram Language. 2018. "NetDrop." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/NetDrop.html.

APA

Wolfram Language. (2018). NetDrop. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/NetDrop.html

BibTeX

@misc{reference.wolfram_2026_netdrop, author="Wolfram Research", title="{NetDrop}", year="2018", howpublished="\url{https://reference.wolfram.com/language/ref/NetDrop.html}", note=[Accessed: 01-September-2026]}

BibLaTeX

@online{reference.wolfram_2026_netdrop, organization={Wolfram Research}, title={NetDrop}, year={2018}, url={https://reference.wolfram.com/language/ref/NetDrop.html}, note=[Accessed: 01-September-2026]}